This exploratory, developmental study will capture and code the content of adolescents' activity on the most popular social networking site on the Internet, Face book. According to large, national surveys, 73% of teens (12 - 17) use social networking sites (Lenhart, Purcell, Smith, & Zickuhr, 2010); 51% of teens check social networking sites daily, and 22% check more than 10 times per day (Common Sense Media, 2009). Face book communication will be captured and coded for a sample of adolescents participating in an ongoing longitudinal study of origins and outcomes of social and physical aggression (NICHD R01 HD060995, Social Aggression: Growth and Outcomes). This multi-method, multi-informant study began when participants were 9 years old and in the 3rd grade and has involved yearly assessments of participants' social aggression and victimization, relationships, and psychological adjustment. Three years ago, in the summer before the sample started high school (9th grade), participants were given BlackBerry devices with service plans paid for by the investigators, including unlimited text messaging, internet access for email, and a limited number of voice minutes. Since the fall of 2008, we have been capturing the content of all text messaging and email sent and received on these BlackBerry devices. At the time of the proposed study of Face book communication, the sample will be 17 or 18 years old and in the 12th grade (N = 200). In each year of the proposed two year study, adolescent participants and their parents will be asked to grant permission for the investigators to access the adolescents' Face book communication by installing a Face book application developed by a company called Arkovi. The Face book application will capture the content of participants' Face book communication: including the wall posts, status updates, inbox, and photo albums. All Face book communication will be captured, not only that on the BlackBerry devices. Face book content will be stored by Arkvoi and maintained in a searchable, flexible online archive maintained by a company called Global Relay for later coding and analysis. The first specific aim will be to examine social aggression and cyber bullying in the context of Face book and how Face book communication relates to offline social aggression and victimization. The second specific aim will be to investigate relations between Face book activity and other forms of electronic communication (i.e., text messaging, email) and to investigate whether different forms of electronic communication relate to positive and negative qualities of relationships with parents, peers, and romantic partners. The third specific aim will be to examine relations between quantity and quality of Face book communication and psychological adjustment. Adding the proposed investigation of Face book communication to this ongoing longitudinal study provides a unique opportunity to examine how Face book communication relates to adolescents' social aggression and victimization, developing social relationships, and psychological adjustment in a developmental period in which youth are transitioning to living away from home and in which symptoms of psychopathology may emerge.